Title is the question. I have an '85 z with the in-cap coil, I also have an '87 distributor w/ the remote coil out of a parts car that no one seems to want to buy. I was just wondering if there are any performance advantages to using the newer style setup?

If the difference is negligible, I will definitely stick with the old setup since it is working, and has less wear on it.

 

It's just smaller and the timing is computer controlled. The older large cap HEI was bulletproof. I'd keep it.

 

I thought that they were both computer controlled.

 

The difference is yours is probably carb'....the remote mount coil and small cap were used so that the tuned port injection plenum/intake would fit. A HEI dist. will not fit behind a TPI intake...

 

I know for a fact that the big cap distributors were used in '85-'86 TPI cars. My car was a 100% stock garage queen when I got her, and It had the big cap distributor. It is TPI. They just have different connectors from the harness, but they have the same color wires. (I am 99% sure it is computer controlled)

So I guess the bigger question is why did GM switch if there is no difference?

 

The original large cap ones were vacuum advance, the later ones were computer controlled.

 

I've heard that both ease of packaging and reliablilty were reasons they switched as well as the small cap remote coil unit supporting slightly higher coil voltages and higher rpm ranges from the factory. The guy I learned about cars from is an avid GM man who's been workin on this stuff since the 60's he said the large cap HEI tended to suffer coil saturation at high rpm levels followed by severe voltage drop.
Personlly i have used both with aftermarket ignitions and I prefer the small cap setup.

 

Exactly the answer I was looking for. I guess, I can just take my time, and freshen up the small cap one with hi performance components and just install it when I do the heads and cam swap a ways down the line.

Thanks!

 

I too have wondered why GM moved to the small cap distributors. Me, I prefer them over the large cap design. Along the lines of what is mentioned by Vette9190, I always thought that the coils where just too small.

However, it is interesting to note that even when GM moved to the small cap distributors on the f-body's, they stayed with the large cap on the Corvettes.

One advantage of the larger cap is a greater separation of the plug wire terminals inside of the cap. Less change of arc-over.

RBob.